Page:A Treatise on the Diseases of the Bones.djvu/206

190 ward by Mr, in the 58th page of his treatise. "In the common case of fracture of the patella, by the sudden action of the quadriceps extensor, the bone is broken, and the pieces drawn separate, without that degree of violence which is necessary to produce re-union by bone. But when the patella is broken, by a blow upon it, as by the kick of a horse, there is not only less retraction, but the injury, bloody effusion, tumefaction, and rigidity of the parts, resemble that which attends the fracture of any other bone, and the fragments unite by bone." The primary cause of union by osseous matter of fracture of the patella, occasioned by the irregular and violent contraction of the extensor muscles, may be partly attributed to the degree of pain which the patient experiences in consequence of the accident. When the pain is trifling, it is a difficult matter to prevent the patient from moving his knee; but when it is severe, as is always the case when the patella has been shattered by the kick of a horse, the blow of a bludgeon, or in consequence of a fall from a scaffold, no arguments are necessary to persuade him to keep his limb extended and at rest. From Mr 's statements on this point, one would